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A000869 Number of switching networks with C(2,n) acting on domain and GL(3,Z2) acting on range.
(Formerly M3620 N1470)
1
4, 27, 14056, 104751025086, 14737381492157353997140846, 583807825091767184801127161305581049499763751729421166 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Next term has 112 digits. - Sean A. Irvine, Jan 24 2012
REFERENCES
M. A. Harrison, On the number of classes of switching networks, J. Franklin Instit., 276 (1963), 313-327.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
EXAMPLE
a(n) = (8^(2^n) + 22*2^(2^n + 2^(n-1) + n) - 22*2^(2^n + 2^(n-1)) + 21*4^(2^n) + 56*2^(2^n) + 42*2^(n + 2^n) + 56*2^(2^(n-1) + n) - 56*2^(2^(n-1)) + 48*2^n)/(168*2^n). - Sean A. Irvine, Jan 24 2012
PROG
(Magma) [(8^(2^n)+22*2^(2^n+2^(n-1)+n)-22*2^(2^n+2^(n-1))+21*4^(2^n)+56*2^(2^n)+42*2^(n+2^n)+56*2^(2^(n-1)+n)-56*2^(2^(n-1))+48*2^n)/(168*2^n): n in [1..11]]; // Vincenzo Librandi, Mar 28 2012
CROSSREFS
Sequence in context: A132646 A254866 A292968 * A132640 A307031 A306823
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Jan 23 2012
STATUS
approved

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Last modified February 23 04:31 EST 2024. Contains 370267 sequences. (Running on oeis4.)